# 1 函数 round() 通常让小数精确到小数点后多少位，其中小数位数是由第二个实参指定的。然
#   而，如果将第二个实参指定为负数， round() 将圆整到最近的10、100、1000等整数倍
# 2  "{:,}"这个字符串格式设置指令，它让Python将数值转换为字符串时在其中插入逗号，
# 例如，输出 1,000,000 而不是 1000000 
import pygame.font
from pygame.sprite import Group
from ship import Ship

class Scoreboard():
    """显示得分信息的类"""
    def __init__(self, ai_settings, screen, stats):
        """初始化显示得分涉及的属性"""
        self.screen = screen
        self.screen_rect = screen.get_rect()
        self.ai_settings = ai_settings
        self.stats = stats
        # 显示得分信息时使用的字体设置
        self.text_color = (30, 30, 30)
        self.font = pygame.font.SysFont(None, 48)
        # 准备包含最高得分和当前得分的图像
        self.prep_score()
        self.prep_high_score()
        # 准备当人物等级的图像
        self.prep_level()
        # 准备所有飞船的图像
        self.prep_ships()

    def prep_score(self):
        """将得分转换为一幅渲染的图像""" 
        rounded_score = int(round(self.stats.score, -1)) 
        score_str = "{:,}".format(rounded_score)
        self.score_image = self.font.render(score_str, True, self.text_color,
        self.ai_settings.bg_color)
        
        self.score_rect = self.score_image.get_rect()           # 将得分放在屏幕右上角
        self.score_rect.right = self.screen_rect.right - 20
        self.score_rect.top = 20

    def prep_high_score(self):
        """将最高得分转换为渲染的图像"""
        high_score = int(round(self.stats.high_score, -1))
        high_score_str = "{:,}".format(high_score)
        self.high_score_image = self.font.render(high_score_str, True,
        self.text_color, self.ai_settings.bg_color)
        
        self.high_score_rect = self.high_score_image.get_rect() #将最高得分放在屏幕顶部中央
        self.high_score_rect.centerx = self.screen_rect.centerx
        self.high_score_rect.top = self.score_rect.top

    def prep_level(self):
        """将等级转换为渲染的图像"""   
        self.level_image = self.font.render(str(self.stats.level), True,
        self.text_color, self.ai_settings.bg_color)
        
        self.level_rect = self.level_image.get_rect()            # 将等级放在得分下方
        self.level_rect.right = self.score_rect.right   
        self.level_rect.top = self.score_rect.bottom + 10

    def prep_ships(self):
        """显示还余下多少艘飞船""" 
        self.ships = Group() 
        for ship_number in range(self.stats.ships_left):
            ship = Ship(self.ai_settings, self.screen) 
            ship.rect.x = 10 + ship_number * ship.rect.width 
            ship.rect.y = 10 
            self.ships.add(ship)

    def show_score(self):
        """在屏幕上显示得分以及最高得分"""
        self.screen.blit(self.score_image, self.score_rect)
        self.screen.blit(self.high_score_image, self.high_score_rect)
        self.screen.blit(self.level_image, self.level_rect)
        # 绘制飞船
        self.ships.draw(self.screen)

    